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Service bulletins for the 2018 Audi S4

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

796 on file from NHTSA, as of 2026-10-19.

By type

By component

By trouble code

By topic

Bulletins, newest first
A9021002032113_52021-05-06. Service bulletin. EQUIPMENT. This information bulletin contains a background on the outside air temperature reading.
A5721762055916_32021-05-06. Service bulletin. STRUCTURE; ELECTRICAL SYSTEM. This bulletin contains a software update for the DTC B14FF29 and the message "Child lock: malfunction!" appears in the instrument cluster.
A9021992063038_12021-05-06. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL; ELECTRICAL SYSTEM. This informational bulletin explains why the version information pops-up.
A4821972063041_12021-05-06. Service bulletin. STEERING. This buletin contains a software update when there is a red steering warning lamp and DTC B200000 is stored.
A6421792047061_32021-05-06. Service bulletin. EQUIPMENT:OTHER:LABELS. This bulletin contains a cleaning procedure from leftover residue from suction cups or labels.
A9121872062742_12021-05-06. Service bulletin. ELECTRICAL SYSTEM; AIR BAGS. This bulletin contains a software update for when "Safe CP" and Airbag Warning with various DTCs logged.
A5521542062730_12021-05-06. Service bulletin. EQUIPMENT. This bulletin explains why the compartment lid cannot be closed using the buttons on the key sometimes.
A9121862062713_12021-04-06. Service bulletin. EQUIPMENT. This bulletin contains repair instructions for when there is radio static when the rear heater is active.
A5521532062669_12021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin states that this is a normal condition and to not perform any repairs.
A0121012054893_52021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for documenting the "Please reduce Oil Level" message in the instrument cluster potentially with an Engine Warmup request.
A9421362023322_32021-04-06. Service bulletin. EXTERIOR LIGHTING. This informational bulletin contains information on the different shading of LED headlights.
A8021112062583_12021-04-06. Service bulletin. EQUIPMENT. This bulletin contains instructions for addressing an insufficient or uneven heating performance from the HVAC system.
A4821962055733_22021-04-06. Service bulletin. STEERING. This bulletin contains repair instructions for repositioning the intermediate steering shaft when there is squeaking noises from the steering column.
A1321132062387_12021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains instructions for determining if a repair is needed when coolant touches a poly V-belt and/or a toothed belt.
SM 17-20212021-04-06. Service bulletin. ELECTRICAL SYSTEM. This special notice is to inform dealers to return the parts listed if it meets the criteria provided.
A9121782050565_32021-04-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains general software update instructions for vehicles with PR Code 7UH.
A9121762037809_82021-04-06. Service bulletin. EQUIPMENT. This informational bulletin contains instructions about updating the navigation map.
A3921422051558_62021-04-06. Service bulletin. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. This bulletin contains repair instructions for when the message "four-wheel drive malfunction" shows up sporadically in the instrument cluster with DTC C05ED00.
A1921132058767_72021-04-06. Service bulletin. EQUIPMENT. This bulletin contains instructions for DTCs P218100, P017B00, P308100, and P01E400.
A1921122061918_22021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin provides guidance on diagnosing a coolant light concern with normal coolant level in the tank.
A1021212059446_42021-04-06. Service bulletin. ENGINE AND ENGINE COOLING. This bulletin contains repair instructions for when oil is lost in the engine compartment.
A0121992054893_42021-04-06. Service bulletin. ELECTRICAL SYSTEM. This bulletin contains instructions for documenting the "Please reduce Oil Level" message in the instrument cluster potentially with an Engine Warmup request.
A9121702062267_12021-03-04. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. This bulletin states to not perform any repairs and show the customer how to manually re-enable the map.
A4721082055646_22021-03-04. Service bulletin. SERVICE BRAKES. This bulletin contains repair instructions for when the vehicle sporadically does not start and there is a hard brake pedal concern.
A4621252054385_22021-03-04. Service bulletin. EQUIPMENT; SERVICE BRAKES. This informational contains an explanation for when the customer hears creaking noises when braking at almost standstill (crawling when pulling away or briefly before standstill).

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.